This device relates to a device and method for the treatment of alterosclerosis, and more particularly to the removal of diseased tissue from an artery.
An artery is comprised of three layers including the outer layer or adventitia, a middle or smooth muscle layer, and an intima-tunica or intimal lining. Deposits collect on the intimal wall and result in stenosis, blockage or complete obstruction of the flow of blood through the artery. The procedure for removal of a diseased inner layer from within the adventitia is known as an endarterectomy, and a new and healthy intima will grow from the adventitia.
Devices for the removal of the intima are well known. Typically, an appropriately sized cylindrical ring with a blunt distal edge known as a ring stripper is inserted between the adventitia and intima and pushed along the artery to separate the intima from the outer wall of the vessel. At spaced intervals, an incision is made through the intima and the separated intima may then be withdrawn from the artery. An intima separation and cutting instrument is described in the Kalmann and Moll U.S. Pat. No. 5,843,102 dated Dec. 1, 1998 and a discussion thereof may be found in Ho et al, "The Mollring Cutter Remote Endarterectomy", J. Endovascular Surgery, 1995; 2:278-287.
Because the intima is generally separated from the outer wall by the presence of the ring stripper for some axial distance beyond the place where the intima is severed, a flap of the intima remains attached to the outer wall and may itself serve as an obstruction. It is further known to address this intima flap problem by vascular stents, but such stents are expensive and reduce the flexibility of the vessel. An alternative is described in the U.S. Pat. No. 5,820,629 dated Oct. 13, 1998 in which a smooth transition in the intimal lining is achieved by an electrocautery coil or a radially extending blade.
Instruments such as those described above are of course small, and tend to be very expensive and complicated to build. Sharp edges are potentially a problem because of the inherent risk of perforation of the outer wall of the artery. In addition, the diameter of the ring used to strip the intima from the outer wall of the artery is generally a constant and incapable of deformation to accommodate changes in the size of an artery for a specific patient or different patients. In addition, the rigidity of the ring and the elongated handle of commercially available ring strippers insures the ability to push the ring through the artery, but this rigidity also increases the risk, of perforation of the outer wall of the artery and makes it more difficult for the instrument to follow the artery through any deviations from a straight line.
It is accordingly an object of the present invention to provide a novel endarterectomy device and method which obviates many of the deficiencies of known devices and methods, which is simple in construction, readily modifiable in both size and shape to accommodate the wishes of the patient or the physician, easy to use, inexpensive, usable in either direction and constructed and configurable to assist dissection while preventing perforation of the outer wall of the artery. In some embodiments, the device may be insertable through a catheter significantly smaller than the artery.
These and many other objects and advantages of the present invention will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims, the appended drawings, and the following detailed description of the preferred embodiments.